Photomobile polymer materials: from nano to macro

Polysiloxane Side-Chain Azobenzene-Containing Liquid Single Crystal Elastomers for Photo-Active Artificial Muscle-Like Actuators

“…20 Highly noteworthy photo-actuating properties have been successfully achieved in polydomain azobenzene-based liquid-crystalline elastomeric materials by Ikeda. [21][22][23][24][25][26] These materials show a great variety of three-dimensional contraction and expansion movements when they are exposed to polarised light of the appropriate wavelength. Within the last few years, it has been reported that it is possible to control the bending direction of the LCE film depending on the role of the azoderivative within the elastomeric network, that is, if the azo-chromophore acts as a cross-linker or as a simply pendant group.…”

New strategies and implications for the photoalignment of liquid crystalline polymers

“…This approach has provided various types of smart, light-responsive materials 1 exhibiting surface-mediated photoalignment of LC materials, 2-6 photoinduced phase transitions, 7-12 photoorientation/addressing of polymer thin films, 13-18 photoinduced mass migrations, [19][20][21][22][23][24][25][26][27][28] phototactic sliding motions, 29-31 photo-driven motions and morphology of monolayers, 32-35 and macroscopic photomechanical deformations. [36][37][38][39][40][41][42][43][44][45][46] Photoalignment research and technology started in 1988 with the discovery of the reversible alignment control of nematic LCs by the photoisomerization of azobenzene on a substrate surface (Figure 1) by Ichimura et al 47 It was demonstrated that the E/Z (trans/cis) photoisomerization of an azobenzene monolayer on a substrate can switch the alignment of nematic LC molecules between the homeotropic and planar modes. This active functional surface was dubbed a 'command surface' or 'command layer.'…”

“…This approach has provided various types of smart, light-responsive materials 1 exhibiting surface-mediated photoalignment of LC materials, [2][3][4][5][6] photoinduced phase transitions, [7][8][9][10][11][12] photoorientation/addressing of polymer thin films, [13][14][15][16][17][18] photoinduced mass migrations, [19][20][21][22][23][24][25][26][27][28] phototactic sliding motions, [29][30][31] photo-driven motions and morphology of monolayers, [32][33][34][35] and macroscopic photomechanical deformations. [36][37][38][39][40][41][42][43][44][45][46] Photoalignment research and technology started in 1988 with the discovery of the reversible alignment control of nematic LCs by the photoisomerization of azobenzene on a substrate surface (Figure 1) by Ichimura et al …”

“…Considering this point, the development of methods for controlling materials at the mesoscopic level should be meaningful and alluring because of the material chemistry. Mesoscopic systems are expected to bridge the photoresponsive phenomena of different size ranges between molecular [75][76][77] and macroscopic functions [36][37][38][39][40][41][42][43][44][45][46] and provide panoscopic views of photoresponsive smart materials. …”

Nano-Zirconium Tungstate Reinforced Liquid Crystalline Thermosetting Composites with Near Zero Thermal Expansion

“…Liquid crystalline elastomers (LCE) represent a special class of SMPs that are defined by a reversible LC phase transition and a unique coupling between LC mesogens and polymer networks [96][97][98][99] . They exhibit reversible shape change when exposed to external stimuli, such as heat 96,[100][101][102][103][104][105] , light [106][107][108][109][110][111][112] , or magnetic field [113][114] , which makes them excellent candidates for artificial muscles, sensors, lithography substrates, and shape memory materials. A number of LCEs with different LC phases and network structures have been synthesized and characterized, including nematic main-chain, smectic mainchain, nematic side-chain, and smectic side-chain LCEs.…”